<!DOCTYPE html>
<html>
<head>
    <title>表格作业</title>
</head>
<style>
    table tr:nth-child(2n) {
        background-color: blueviolet;
    }
    table tr:nth-child(2n+1) {
        background-color: rgb(187, 15, 15);
    }
    table tr:first-child {
        background-color: #fff;
    }
</style>
<body>
        <table border="1">
         <tr>
            <th>月份</th>
            <th>收入</th>
            <th>支出</th>
            <th>盈亏</th>
         </tr>
         <tr>
            <td>一月</td>
            <td>2800</td>
            <td>1800</td>
            <td>1000</td>
         </tr>
         <tr>
            <td>二月</td>
            <td>2500</td>
            <td>2800</td>
            <td>1000</td>
         </tr>
         <tr>
            <td>三月</td>
            <td>5300</td>
            <td>4600</td>
            <td>700</td>
         </tr>
         <tr>
            <td>四月</td>
            <td>5300</td>
            <td>4600</td>
            <td>700</td>
         </tr>
         </tr>
         <tr>
            <td>五月</td>
            <td>5300</td>
            <td>4600</td>
            <td>700</td>
         </tr>
         <tr>
            <td>六月</td>
            <td>5300</td>
            <td>4600</td>
            <td>700</td>
         </tr>
         <tr>
            <td>七月</td>
            <td>5300</td>
            <td>4600</td>
            <td>700</td>
         </tr>
         <tr>
            <td>八月</td>
            <td>5300</td>
            <td>4600</td>
            <td>700</td>
         </tr>
         <tr>
            <td>九月</td>
            <td>5300</td>
            <td>4600</td>
            <td>700</td>
         </tr>
         <tr>
            <td>十月</td>
            <td>5300</td>
            <td>4600</td>
            <td>700</td>
         </tr>
         <tr>
            <td>十一月</td>
            <td>5300</td>
            <td>4600</td>
            <td>700</td>
         </tr>
         <tr>
            <td>十二月</td>
            <td>5300</td>
            <td>4600</td>
            <td>700</td>
         </tr>
         </table>
</body>
</html>